How many questions do Topper attempts ( in avg) Sectional wise ( QA/VARC/DILR) in CAT ??

You need to understand one thing that whether it is a CAT exam or a XAT exam, it is always unpredictive and there are no fixed marks for a certain percentile. As CAT and XAT, both are evaluated on the percentile, not on percentage so it depends on both your performance and also the performance of your colleagues giving the same exam. The marks vs percentile range vary every year.

Still if on an average if you want to know how much to score so as to be among the students where you can get calls from top b-schools like IIMs then you need to atleast aim for 180+ score. Keeping an accuracy level to be 80-90% you need to attempt 20-25 questions in each section.

But as I told earlier this is all just an estimation, give lots of online mock test to know your mistake, realize your potential and come up with your best performance.

All the best!!